21-substituted 6-chloro - 16alpha,17alpha-isopropyl-idenedioxy-pregna - 4,6 - diene-3,20-dione and method of preparing the same

ABSTRACT

THE COMPOUNDS 21-CHLORO OR 21-METHANESULFONYLOXY-6CHLORO-16A,17A-ISOPROPYLIDENDIOXYPREGNA-4,6 - DIENE - 3, 20-DIONE ARE DESCRIBED ALONG WITH METHODS OF PREPARING THE SAME. THEY ARE USEFUL AS ANTI-FERTILITY AGENTS.

United States Patent O 3,579,508 ZI-SUBSTITUTED 6-CHLORO 16a,17u-ISOPROPYL- IDENEDIOXY-PREGNA 4,6 DlENE-3,20-DIONE AND METHOD OF PREPARING THE SAME Milton David Heller, New City, N.Y., Robert Herman Lenhard, Paramus, N.J., and Seymour Bernstein, New City, N.Y., assignors to American Cyanamid Company, Stamford, Conn. No Drawing. Filed Mar. 20, 1969, Ser. No. 808,983 Int. Cl. C07c 173/00 US. Cl. 260239.55 1 Claim ABSTRACT OF THE DISCLOSURE The compounds 21-chloro or 2l-methanesulfonyloXy-6- chloro-l6a,l7a-isopropylidendioxypregna-4,6 diene 3, 20-dione are described along with methods of preparing the same. They are useful as anti-fertility agents.

SUMMARY OF THE INVENTION This invention relates to novel chloropregnadiene acetonides. More particularly, it relates to 6-ChlOIO-l61x,l7x isopropylidenedioxypregnadienes and method of preparing the same.

The present compounds may be illustrated by the following formula:

wherein R is selected from the group consisting of methanesulfonyloxy and chlorine.

The present compounds are solids having a definite melting point. They are soluble in pyridine and in pure form are white solids.

The present compounds are prepared by starting with 313,21-diacetoxy-l6a,17a-isopropylidenedioxypregn-S en- 20-one (Compound I of flowsheet hereinafter) which is reacted With m-chloroperbenzoic acid in a solvent such as methylene chloride. The product obtained is 3 5,2l-diacetoxy-Sg, 6g-epoxy-l6a,17u-isopropylidenedioxypregnan-ZO- one (Compound II). The latter compound when treated with periodic acid produces 3,8,2l-diacetoxy-a,6fl-dihydroxy-16a,17a-isopropylidenedioxypregnan-ZO-one (Compound III). On treating this compound with chromic acid in sulfuric acid 35,21-diacetoxy-5a-hydroxy-16a,l7a-isopropylidenedioxypregnane-6,20-dione (Compound IV) is obtained. The latter compound when treated with thionyl chloride in pyridine produces 3,8,21-diacetoxy-16w,17a-isopropylidenedioxypregn-4-ene-6,20-dione (Compound V). On treating this compound with phosphorus pentachloride in a solvent 3/532l-diacetoxy-6-chloro-l6a,l7a-isopropylidenedioxypregnat,6-dien 2O one (Compound- VIA) is obtained. The latter compound when heated with an alkali metal carbonate produces 6-chloro-3fi,2l-dihydroXy-l6a,l7rx-isopropylidenedioxypregna-4,6 dien 20- one (Compound VIB). When the latter compound is contacted with 2,3-dich1oro-5,6-dicyanobenzoquinone in a solvent the product 6-chloro-2l-hydroxy-l6a,17a-isopropylidenedioxypregnat,6-diene-3,ZO-dione (Compound VIIA) is obtained. On treating compound (VIIA) with acetic anhydride in pyridine the product 21-acetoXy-6-chloroice FLOWSHEET (EH20 R C=O H30 0 CH3 H3 0 0 C H3 VIA Rimcetyl VIB R1=H VIIA R;=OH

VIIB R =acetoxy VIIC R3=OSO2CH3 VIID R3=O1 In the above flowsheet, R is loweralkanoyl, R is lower alkanoyl or hydrogen and R is lower alkanoyl, hydroxyl, methanesulfonyloxy or chlorine.

The present compounds such as 6,21-dichloro-16a,17aisopropylidenedioxypregna-4,6-diene-3,20-dione are antifertility agents and for example is four times more active than the commercial product 17a-acetoxy-6-chloropregna- 4,6-diene-3,20-dione.

DETAILED DESCRIPTION The following examples describe in detail the preparation of the compounds of the present invention.

EXAMPLE 1 Preparation of 33,21-diacetoxy-,6.-epoxy-16a,17 xisopropylidenedioxypregnan-ZO-one (II) A solution of m-chloroperbenzoic acid (500 mg.) in methylene chloride (25 ml.) is added to a solution of 3,8,21-diacetoxy 1601,17 isopropylidenedioxypregn-S- en-20-oue (I) (500 mg.) in methylene chloride (25 ml.). After standing at room temperature for 66 hours, the reaction mixture is poured into saturated sodium carbonate solution and the organic extract is washed with water, dried and evaporated. The crude oxide (509 mg, melting point 199-208 C., homogeneous by thin layer chromatographic analysis is crystallized from methanol to afford 4 422 mg. of the above product, melting point 213-215 C. One additional crystallization did not alter the melting point but NMR analysis indicated the constant melting material is a mixture of approximately ozand 25% fi-oxides.

EXAMPLE 2 Preparation of 35,21-diacetoxy-5a,6 8-dihydroxy-16a,17aisopropylidenedioxypregnan-ZO-one (III) A solution of 3,8,21-diacetoxy-5,6-epoxy-160,17m-iso propylidenedioxypregnan-20-one (Example 1) mg.) in acetone (6 ml.) is treated with periodic acid mg.) in water (2 ml.). The reaction mixture is refluxed for 1 hour and then concentrated with the simultaneous addition of water to afford a crystalline precipitate. The product is filtered and washed with Water to yield mg, melting point 264-267 C. Two crystallizations from acetone-water gives the analytical sample, melting point 268.5-270 C.

EXAMPLE 3 Preparation of 3;3,21-diacetoxy5 u-hydroxy-1'6a,17 xisopropylidenedioxypregnane-6,20-dione (IV) A solution of 8 N chromic acid in sulfuric acid (5.6 ml.) is added dropwise over a period of 8 minutes to a stirred solution of 3,3,21 diacetoxy 5ix,6,8 dihydroxy- 16a,17a-isopropylidenedioxypregnan-ZO-one (Example 2), (6.89 g.) in acetone ml.) at room temperature. After allowing the reaction to proceed for an additional 8 minutes, the reaction mixture is poured into a large volume of ice-water and the product is filtered and washed with water to afford 6.24 g., melting point ca. 132-157" C. with previous softening at 118 C., bubbles in melt, partial resolidification at ca. 170 C. and remelting at ca. -195 C. A portion is recrystallized twice from acetone-water to afford the analytically pure sample, melting point slow effervescence from ca. 122 C. on with some resolidification at ca. 165-170 'C. and remelt ing at ca. 189-193 C. (unchanged after drying under reduced pressure overnight at 110 C.).

EXAMPLE 4 Preparation of 35,21-diacetoxy-l6a,l7a-isopropylidenedioxypregnal-ene-6,20-dione (V) A solution of 3,6,21-diacetoxy-5a-hydroxy-16a,17a-isopropylidenedioxypregnane-6,20-dione (Example 3) (156 mg.) in pyridine (1.5 ml.) is cooled to 0 C. and thionyl chloride (0.15 ml.) is added dropwise 'with swirling. The reaction mixture is allowed to remain at 0 C. for 1 hour, chipped ice is then added and the precipitated product is filtered and washed with Water to afford 135 mg. of the above product, melting point 184.5188 C. Several recrystallizations from acetone-hexane provides the sample for analysis, melting point -l98 C.;

REES 236-237 ma (6 7,100)

EXAMPLE 5 Preparation of 3,8,2l-diacetoxy-G-chloro-l6a,17u-isopropylidenedioxypregna-4,6-dien-20-one (VIA) Phosphorous pentachloride (1.27 g.) is added to a solution of 3,8,21-diacetoxy 160:,17oc -i sopropylidenedioxypregn-4-ene-6,20-dione (Example 4), (1.27 g.) in carbon tetrachloride (60 ml.) and the suspension is shaken at room temperature for 45 minutes. Pyridine (2.6 ml.) is added and the reaction mixture is poured into saturated sodium bicarbonate solution. The organic phase is washed with water, dried and evaporated to a glassy residue, 1.27 g., Amax. 237, 244 and 252.5 mp. (e 12,950, 14,750 and 10,200, respectively). The residue is dissolved in a small amount of benzene and adsorbed on a synthetic magnesium silicate (69 g.). Elution with 2% acetone-hexane (10X 100 ml. fractions) afiords 700 mg. of crystalline solid. Crystallization from acetone-hexane gives the above VIA (640 mg), melting point 115l20 C. bubbles in melt, xmax. 236-237, 243.5 and 252 m (e 19,400, 22,450 and 15,050 respectively). A 300 mg. portion is recrystallized twice from acetone-hexane to give 265 mg., melting point l23.5-127 C.;

x132 235 111,. 6 22,050 243 mu (e 26,050) and 252 m (6 17,700)

EXAMPLE 6 Preparation of 6-chloro-3;8,2l-dihydroxy-16a,17aisopropylidene-dioxypregna-4,6-dien-20-one (VIB) A solution of 3 9,2l-diacetoxy-6-chloro-16a,l7u-isopropylidenedioxypregna-4,6-dien-20-one (Example 5) (330 mg. and potassium bicarbonate (130 mg.) in aqueous methanol (25 ml.) is refluxed under an atmos phere of argon for 30 minutes. The reaction mixture is cooled to room temperature and water is added to the point of turbidity to precipitate long white needles. After cooling, the product is filtered and washed with water to give 222 mg. of the above compound, melting point 202203.5 C.;

REES 235.5, 243 and 251.5 m (6 19,450; 23,000 and 15,300, respectively) EXAMPLE 7 Preparation of 6-chl0ro-21-hydroxy-16u,17a-isopropylidenedioxypregna-4,6-diene-3,20-dione (VIIA) 2,3-dichloro-5,6-dicyanobenzoquinone (697 mg.) is added to a solution of 6-ch1oro-3B,2l-dihydroxy-16u-isopropylidenedioxypregnal,6-dien-20-one (Example 6) 1.39 g. in peroxide-free dioxane (25 ml.), and the reaction mixture is allowed to stand at room temperature for 18 hours. The precipitated hydroquinone is filtered and washed with a small amount of dioxane. The filtrate is evaporated and the residue is dissolved in methylene chloride and adsorbed on a small pad of activated magnesium silicate to remove any residual hydroquinone, Elution with approximately 250 ml. of methylene chloride and evaporation gives the product as a glass in quantiative yield. VIIA resisted crystallization and is characterized as the acetate VIIB (vide infra). Spectral and thin layer chromatographic analysis indicated that the crude alcohol is suitable for further transformations.

EXAMPLE 8 Preparation of 21-acetoxy-6-chloro-16a,l7a-isopropylidenedioxypregna-4,6-diene-3,20-dione (VIIB) A solution of 6-chloro-2l-hydroxy-l6a,17a-isopr0pylidenedioxypregna-4,6-diene-3,20-dione (Example 7) (100 mg.) in pyridine (1 m1.) and acetic anhydride (0.5 ml.) is allowed to stand at room temperature for 18.5 hours. The reaction mixture is poured into ice-water and the product is filtered and washed With water to give the above product, 102 mg., melting point 186-190 C. Two recrystallizations from acetone-hexane and two from acetone-water affords the analytical sample, melting point 195.5-l97 C.;

EXAMPLE 9 Preparation of 6-chloro-16oz,17a-isoproyplidenedioxy-21- methane-sulfonyloxypregna-4,6-diene-3,20-dione (VIIC) Methane sulfonyl chloride (0.56 ml.) is added dropwise with swirling to a cold solution of 6-chloro-21-hydroxy 16a,17a isopropylidenedioxypregna 4,6-dione 3,20-dione (Example 7), (1.36 g.) in pyridine (10 ml.). After standing at 3 C. for 19 hours, the reaction mixture is poured into ice-water and the precipitated product is collected and washed with water to aflord the above compound, 1.45 g., melting point 106-120 C. with previous softening at ca. C. Infrared and thin layer chromatographic analyses indicate that the mesylate is of sufficient purity for the next reaction.

EXAMPLE 10 Preparation of 6,2l-dichloro-l6u,17a-isopropylidenedioxypregna-4,6-diene-3,20-dione (VIlD) A solution of 6-ChlOl'0-16ot,17ot-iSOPI0Ylid6I16dlOXY-21- methanesulfonyloxypregna-4,6-diene-3,20-dione (Example 9) (214 mg.) and lithium chloride (60 mg.) in dimethylformamide 10 ml.) is refluxed for 30 minutes. The reaction mixture is evaporated, water is added and the crude soild (179 mg.) is filtered, washed with water and recrystallized from acetone-hexane to give the above prodnet, mg., melting point 258.5-260" C. with decomposition. The product is dissolved in methylene chloride and filtered through a small pad of activated magnesium silicate to remove a small amount of yellow color, The evaporated filtrate is crystallized twice from acetone-hexane to afford the analytical sample, melting point 264- 265.5 C., decomposition at 267 C.;

x1552 284.5 my (6 25,150) What is claimed is: 1. The compound 6-chloro-16a,17a-isopropylidenedioxy-21-methanesulfonyloxypregna-4,6-diene-3,20-dione.

References Cited UNITED STATES PATENTS 3,053,838 9/1962 Fried 260-23955 3,213,087 10/1965 Bowers et a1. 260-23955 3,234,214 2/1966 DiasSi et a1 260239.55

ELBERT L. ROBERTS, Primary Examiner 

